/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#ifndef http_parser_h
#define http_parser_h

#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stddef.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Also update SONAME in the Makefile whenever you change these. */
#define HTTP_PARSER_VERSION_MAJOR 2
#define HTTP_PARSER_VERSION_MINOR 9
#define HTTP_PARSER_VERSION_PATCH 2

#include <stddef.h>
#if defined(_WIN32) && !defined(__MINGW32__) && \
        (!defined(_MSC_VER) || _MSC_VER < 1600) && !defined(__WINE__)
#include <BaseTsd.h>
typedef __int8 int8_t;
typedef unsigned __int8 uint8_t;
typedef __int16 int16_t;
typedef unsigned __int16 uint16_t;
typedef __int32 int32_t;
typedef unsigned __int32 uint32_t;
typedef __int64 int64_t;
typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif

/* Compile with -DHTTP_PARSER_STRICT=0 to make less checks, but run
 * faster
 */
#ifndef HTTP_PARSER_STRICT
#define HTTP_PARSER_STRICT 1
#endif

/* Maximium header size allowed. If the macro is not defined
 * before including this header then the default is used. To
 * change the maximum header size, define the macro in the build
 * environment (e.g. -DHTTP_MAX_HEADER_SIZE=<value>). To remove
 * the effective limit on the size of the header, define the macro
 * to a very large number (e.g. -DHTTP_MAX_HEADER_SIZE=0x7fffffff)
 */
#ifndef HTTP_MAX_HEADER_SIZE
#define HTTP_MAX_HEADER_SIZE (80 * 1024)
#endif

typedef struct http_parser http_parser;
typedef struct http_parser_settings http_parser_settings;


/* Callbacks should return non-zero to indicate an error. The parser will
 * then halt execution.
 *
 * The one exception is on_headers_complete. In a HTTP_RESPONSE parser
 * returning '1' from on_headers_complete will tell the parser that it
 * should not expect a body. This is used when receiving a response to a
 * HEAD request which may contain 'Content-Length' or 'Transfer-Encoding:
 * chunked' headers that indicate the presence of a body.
 *
 * Returning `2` from on_headers_complete will tell parser that it should not
 * expect neither a body nor any futher responses on this connection. This is
 * useful for handling responses to a CONNECT request which may not contain
 * `Upgrade` or `Connection: upgrade` headers.
 *
 * http_data_cb does not return data chunks. It will be called arbitrarily
 * many times for each string. E.G. you might get 10 callbacks for "on_url"
 * each providing just a few characters more data.
 */
typedef int (*http_data_cb)(http_parser *, const char *at, size_t length);
typedef int (*http_cb)(http_parser *);


/* Status Codes */
#define HTTP_STATUS_MAP(XX)                                                   \
    XX(100, CONTINUE, Continue)                                               \
    XX(101, SWITCHING_PROTOCOLS, Switching Protocols)                         \
    XX(102, PROCESSING, Processing)                                           \
    XX(200, OK, OK)                                                           \
    XX(201, CREATED, Created)                                                 \
    XX(202, ACCEPTED, Accepted)                                               \
    XX(203, NON_AUTHORITATIVE_INFORMATION, Non - Authoritative Information)   \
    XX(204, NO_CONTENT, No Content)                                           \
    XX(205, RESET_CONTENT, Reset Content)                                     \
    XX(206, PARTIAL_CONTENT, Partial Content)                                 \
    XX(207, MULTI_STATUS, Multi - Status)                                     \
    XX(208, ALREADY_REPORTED, Already Reported)                               \
    XX(226, IM_USED, IM Used)                                                 \
    XX(300, MULTIPLE_CHOICES, Multiple Choices)                               \
    XX(301, MOVED_PERMANENTLY, Moved Permanently)                             \
    XX(302, FOUND, Found)                                                     \
    XX(303, SEE_OTHER, See Other)                                             \
    XX(304, NOT_MODIFIED, Not Modified)                                       \
    XX(305, USE_PROXY, Use Proxy)                                             \
    XX(307, TEMPORARY_REDIRECT, Temporary Redirect)                           \
    XX(308, PERMANENT_REDIRECT, Permanent Redirect)                           \
    XX(400, BAD_REQUEST, Bad Request)                                         \
    XX(401, UNAUTHORIZED, Unauthorized)                                       \
    XX(402, PAYMENT_REQUIRED, Payment Required)                               \
    XX(403, FORBIDDEN, Forbidden)                                             \
    XX(404, NOT_FOUND, Not Found)                                             \
    XX(405, METHOD_NOT_ALLOWED, Method Not Allowed)                           \
    XX(406, NOT_ACCEPTABLE, Not Acceptable)                                   \
    XX(407, PROXY_AUTHENTICATION_REQUIRED, Proxy Authentication Required)     \
    XX(408, REQUEST_TIMEOUT, Request Timeout)                                 \
    XX(409, CONFLICT, Conflict)                                               \
    XX(410, GONE, Gone)                                                       \
    XX(411, LENGTH_REQUIRED, Length Required)                                 \
    XX(412, PRECONDITION_FAILED, Precondition Failed)                         \
    XX(413, PAYLOAD_TOO_LARGE, Payload Too Large)                             \
    XX(414, URI_TOO_LONG, URI Too Long)                                       \
    XX(415, UNSUPPORTED_MEDIA_TYPE, Unsupported Media Type)                   \
    XX(416, RANGE_NOT_SATISFIABLE, Range Not Satisfiable)                     \
    XX(417, EXPECTATION_FAILED, Expectation Failed)                           \
    XX(421, MISDIRECTED_REQUEST, Misdirected Request)                         \
    XX(422, UNPROCESSABLE_ENTITY, Unprocessable Entity)                       \
    XX(423, LOCKED, Locked)                                                   \
    XX(424, FAILED_DEPENDENCY, Failed Dependency)                             \
    XX(426, UPGRADE_REQUIRED, Upgrade Required)                               \
    XX(428, PRECONDITION_REQUIRED, Precondition Required)                     \
    XX(429, TOO_MANY_REQUESTS, Too Many Requests)                             \
    XX(431, REQUEST_HEADER_FIELDS_TOO_LARGE, Request Header Fields Too Large) \
    XX(451, UNAVAILABLE_FOR_LEGAL_REASONS, Unavailable For Legal Reasons)     \
    XX(500, INTERNAL_SERVER_ERROR, Internal Server Error)                     \
    XX(501, NOT_IMPLEMENTED, Not Implemented)                                 \
    XX(502, BAD_GATEWAY, Bad Gateway)                                         \
    XX(503, SERVICE_UNAVAILABLE, Service Unavailable)                         \
    XX(504, GATEWAY_TIMEOUT, Gateway Timeout)                                 \
    XX(505, HTTP_VERSION_NOT_SUPPORTED, HTTP Version Not Supported)           \
    XX(506, VARIANT_ALSO_NEGOTIATES, Variant Also Negotiates)                 \
    XX(507, INSUFFICIENT_STORAGE, Insufficient Storage)                       \
    XX(508, LOOP_DETECTED, Loop Detected)                                     \
    XX(510, NOT_EXTENDED, Not Extended)                                       \
    XX(511, NETWORK_AUTHENTICATION_REQUIRED, Network Authentication Required)

enum http_status
{
#define XX(num, name, string) HTTP_STATUS_##name = num,
    HTTP_STATUS_MAP(XX)
#undef XX
};


/* Request Methods */
#define HTTP_METHOD_MAP(XX)          \
    XX(0, DELETE, DELETE)            \
    XX(1, GET, GET)                  \
    XX(2, HEAD, HEAD)                \
    XX(3, POST, POST)                \
    XX(4, PUT, PUT)                  \
    /* pathological */               \
    XX(5, CONNECT, CONNECT)          \
    XX(6, OPTIONS, OPTIONS)          \
    XX(7, TRACE, TRACE)              \
    /* WebDAV */                     \
    XX(8, COPY, COPY)                \
    XX(9, LOCK, LOCK)                \
    XX(10, MKCOL, MKCOL)             \
    XX(11, MOVE, MOVE)               \
    XX(12, PROPFIND, PROPFIND)       \
    XX(13, PROPPATCH, PROPPATCH)     \
    XX(14, SEARCH, SEARCH)           \
    XX(15, UNLOCK, UNLOCK)           \
    XX(16, BIND, BIND)               \
    XX(17, REBIND, REBIND)           \
    XX(18, UNBIND, UNBIND)           \
    XX(19, ACL, ACL)                 \
    /* subversion */                 \
    XX(20, REPORT, REPORT)           \
    XX(21, MKACTIVITY, MKACTIVITY)   \
    XX(22, CHECKOUT, CHECKOUT)       \
    XX(23, MERGE, MERGE)             \
    /* upnp */                       \
    XX(24, MSEARCH, M - SEARCH)      \
    XX(25, NOTIFY, NOTIFY)           \
    XX(26, SUBSCRIBE, SUBSCRIBE)     \
    XX(27, UNSUBSCRIBE, UNSUBSCRIBE) \
    /* RFC-5789 */                   \
    XX(28, PATCH, PATCH)             \
    XX(29, PURGE, PURGE)             \
    /* CalDAV */                     \
    XX(30, MKCALENDAR, MKCALENDAR)   \
    /* RFC-2068, section 19.6.1.2 */ \
    XX(31, LINK, LINK)               \
    XX(32, UNLINK, UNLINK)           \
    /* icecast */                    \
    XX(33, SOURCE, SOURCE)

enum http_method
{
#define XX(num, name, string) HTTP_##name = num,
    HTTP_METHOD_MAP(XX)
#undef XX
};


enum http_parser_type
{
    HTTP_REQUEST,
    HTTP_RESPONSE,
    HTTP_BOTH
};


/* Flag values for http_parser.flags field */
enum flags
{
    F_CHUNKED = 1 << 0,
    F_CONNECTION_KEEP_ALIVE = 1 << 1,
    F_CONNECTION_CLOSE = 1 << 2,
    F_CONNECTION_UPGRADE = 1 << 3,
    F_TRAILING = 1 << 4,
    F_UPGRADE = 1 << 5,
    F_SKIPBODY = 1 << 6,
    F_CONTENTLENGTH = 1 << 7
};


/* Map for errno-related constants
 *
 * The provided argument should be a macro that takes 2 arguments.
 */
#define HTTP_ERRNO_MAP(XX)                                              \
    /* No error */                                                      \
    XX(OK, "success")                                                   \
                                                                        \
    /* Callback-related errors */                                       \
    XX(CB_message_begin, "the on_message_begin callback failed")        \
    XX(CB_url, "the on_url callback failed")                            \
    XX(CB_header_field, "the on_header_field callback failed")          \
    XX(CB_header_value, "the on_header_value callback failed")          \
    XX(CB_headers_complete, "the on_headers_complete callback failed")  \
    XX(CB_body, "the on_body callback failed")                          \
    XX(CB_message_complete, "the on_message_complete callback failed")  \
    XX(CB_status, "the on_status callback failed")                      \
    XX(CB_chunk_header, "the on_chunk_header callback failed")          \
    XX(CB_chunk_complete, "the on_chunk_complete callback failed")      \
                                                                        \
    /* Parsing-related errors */                                        \
    XX(INVALID_EOF_STATE, "stream ended at an unexpected time")         \
    XX(HEADER_OVERFLOW,                                                 \
       "too many header bytes seen; overflow detected")                 \
    XX(CLOSED_CONNECTION,                                               \
       "data received after completed connection: close message")       \
    XX(INVALID_VERSION, "invalid HTTP version")                         \
    XX(INVALID_STATUS, "invalid HTTP status code")                      \
    XX(INVALID_METHOD, "invalid HTTP method")                           \
    XX(INVALID_URL, "invalid URL")                                      \
    XX(INVALID_HOST, "invalid host")                                    \
    XX(INVALID_PORT, "invalid port")                                    \
    XX(INVALID_PATH, "invalid path")                                    \
    XX(INVALID_QUERY_STRING, "invalid query string")                    \
    XX(INVALID_FRAGMENT, "invalid fragment")                            \
    XX(LF_EXPECTED, "LF character expected")                            \
    XX(INVALID_HEADER_TOKEN, "invalid character in header")             \
    XX(INVALID_CONTENT_LENGTH,                                          \
       "invalid character in content-length header")                    \
    XX(UNEXPECTED_CONTENT_LENGTH,                                       \
       "unexpected content-length header")                              \
    XX(INVALID_CHUNK_SIZE,                                              \
       "invalid character in chunk size header")                        \
    XX(INVALID_CONSTANT, "invalid constant string")                     \
    XX(INVALID_INTERNAL_STATE, "encountered unexpected internal state") \
    XX(STRICT, "strict mode assertion failed")                          \
    XX(PAUSED, "parser is paused")                                      \
    XX(UNKNOWN, "an unknown error occurred")


/* Define HPE_* values for each errno value above */
#define HTTP_ERRNO_GEN(n, s) HPE_##n,
enum http_errno
{
    HTTP_ERRNO_MAP(HTTP_ERRNO_GEN)
};
#undef HTTP_ERRNO_GEN


/* Get an http_errno value from an http_parser */
#define HTTP_PARSER_ERRNO(p) ((enum http_errno)(p)->http_errno)


struct http_parser
{
    /** PRIVATE **/
    unsigned int type : 2;         /* enum http_parser_type */
    unsigned int flags : 8;        /* F_* values from 'flags' enum; semi-public */
    unsigned int state : 7;        /* enum state from http_parser.c */
    unsigned int header_state : 7; /* enum header_state from http_parser.c */
    unsigned int index : 7;        /* index into current matcher */
    unsigned int lenient_http_headers : 1;

    uint32_t nread;          /* # bytes read in various scenarios */
    uint64_t content_length; /* # bytes in body (0 if no Content-Length header) */

    /** READ-ONLY **/
    unsigned short http_major;
    unsigned short http_minor;
    unsigned int status_code : 16; /* responses only */
    unsigned int method : 8;       /* requests only */
    unsigned int http_errno : 7;

    /* 1 = Upgrade header was present and the parser has exited because of that.
   * 0 = No upgrade header present.
   * Should be checked when http_parser_execute() returns in addition to
   * error checking.
   */
    unsigned int upgrade : 1;

    /** PUBLIC **/
    void *data; /* A pointer to get hook to the "connection" or "socket" object */
};


struct http_parser_settings
{
    http_cb on_message_begin;
    http_data_cb on_url;
    http_data_cb on_status;
    http_data_cb on_header_field;
    http_data_cb on_header_value;
    http_cb on_headers_complete;
    http_data_cb on_body;
    http_cb on_message_complete;
    /* When on_chunk_header is called, the current chunk length is stored
   * in parser->content_length.
   */
    http_cb on_chunk_header;
    http_cb on_chunk_complete;
};


enum http_parser_url_fields
{
    UF_SCHEMA = 0,
    UF_HOST = 1,
    UF_PORT = 2,
    UF_PATH = 3,
    UF_QUERY = 4,
    UF_FRAGMENT = 5,
    UF_USERINFO = 6,
    UF_MAX = 7
};


/* Result structure for http_parser_parse_url().
 *
 * Callers should index into field_data[] with UF_* values iff field_set
 * has the relevant (1 << UF_*) bit set. As a courtesy to clients (and
 * because we probably have padding left over), we convert any port to
 * a uint16_t.
 */
struct http_parser_url
{
    uint16_t field_set; /* Bitmask of (1 << UF_*) values */
    uint16_t port;      /* Converted UF_PORT string */

    struct
    {
        uint16_t off; /* Offset into buffer in which field starts */
        uint16_t len; /* Length of run in buffer */
    } field_data[UF_MAX];
};


/* Returns the library version. Bits 16-23 contain the major version number,
 * bits 8-15 the minor version number and bits 0-7 the patch level.
 * Usage example:
 *
 *   unsigned long version = http_parser_version();
 *   unsigned major = (version >> 16) & 255;
 *   unsigned minor = (version >> 8) & 255;
 *   unsigned patch = version & 255;
 *   printf("http_parser v%u.%u.%u\n", major, minor, patch);
 */
static unsigned long http_parser_version(void);

static void http_parser_init(http_parser *parser, enum http_parser_type type);


/* Initialize http_parser_settings members to 0
 */
static void http_parser_settings_init(http_parser_settings *settings);


/* Executes the parser. Returns number of parsed bytes. Sets
 * `parser->http_errno` on error. */
static size_t http_parser_execute(http_parser *parser,
                                  const http_parser_settings *settings,
                                  const char *data,
                                  size_t len);


/* If http_should_keep_alive() in the on_headers_complete or
 * on_message_complete callback returns 0, then this should be
 * the last message on the connection.
 * If you are the server, respond with the "Connection: close" header.
 * If you are the client, close the connection.
 */
static int http_should_keep_alive(const http_parser *parser);

/* Returns a string version of the HTTP method. */
static const char *http_method_str(enum http_method m);

/* Returns a string version of the HTTP status code. */
static const char *http_status_str(enum http_status s);

/* Return a string name of the given error */
static const char *http_errno_name(enum http_errno err);

/* Return a string description of the given error */
static const char *http_errno_description(enum http_errno err);

/* Initialize all http_parser_url members to 0 */
static void http_parser_url_init(struct http_parser_url *u);

/* Parse a URL; return nonzero on failure */
static int http_parser_parse_url(const char *buf, size_t buflen,
                                 int is_connect,
                                 struct http_parser_url *u);

/* Pause or un-pause the parser; a nonzero value pauses */
static void http_parser_pause(http_parser *parser, int paused);

/* Checks if this is the final chunk of the body. */
static int http_body_is_final(const http_parser *parser);

/* Change the maximum header size provided at compile time. */
static void http_parser_set_max_header_size(uint32_t size);

static uint32_t max_header_size = HTTP_MAX_HEADER_SIZE;

#ifndef ULLONG_MAX
#define ULLONG_MAX ((uint64_t) -1) /* 2^64-1 */
#endif

#ifndef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#endif

#ifndef BIT_AT
#define BIT_AT(a, i)                                  \
    (!!((unsigned int) (a)[(unsigned int) (i) >> 3] & \
        (1 << ((unsigned int) (i) &7))))
#endif

#ifndef ELEM_AT
#define ELEM_AT(a, i, v) ((unsigned int) (i) < ARRAY_SIZE(a) ? (a)[(i)] : (v))
#endif

#define SET_ERRNO(e)              \
    do                            \
    {                             \
        parser->nread = nread;    \
        parser->http_errno = (e); \
    } while (0)

#define CURRENT_STATE() p_state
#define UPDATE_STATE(V) p_state = (enum state)(V);
#define RETURN(V)                        \
    do                                   \
    {                                    \
        parser->nread = nread;           \
        parser->state = CURRENT_STATE(); \
        return (V);                      \
    } while (0);
#define REEXECUTE() \
    goto reexecute;

#ifdef __GNUC__
#define LIKELY(X) __builtin_expect(!!(X), 1)
#define UNLIKELY(X) __builtin_expect(!!(X), 0)
#else
#define LIKELY(X) (X)
#define UNLIKELY(X) (X)
#endif

/* Run the notify callback FOR, returning ER if it fails */
#define CALLBACK_NOTIFY_(FOR, ER)                                \
    do                                                           \
    {                                                            \
        assert(HTTP_PARSER_ERRNO(parser) == HPE_OK);             \
                                                                 \
        if (LIKELY(settings->on_##FOR))                          \
        {                                                        \
            parser->state = CURRENT_STATE();                     \
            if (UNLIKELY(0 != settings->on_##FOR(parser)))       \
            {                                                    \
                SET_ERRNO(HPE_CB_##FOR);                         \
            }                                                    \
            UPDATE_STATE(parser->state);                         \
                                                                 \
            /* We either errored above or got paused; get out */ \
            if (UNLIKELY(HTTP_PARSER_ERRNO(parser) != HPE_OK))   \
            {                                                    \
                return (ER);                                     \
            }                                                    \
        }                                                        \
    } while (0)

/* Run the notify callback FOR and consume the current byte */
#define CALLBACK_NOTIFY(FOR) CALLBACK_NOTIFY_(FOR, p - data + 1)

/* Run the notify callback FOR and don't consume the current byte */
#define CALLBACK_NOTIFY_NOADVANCE(FOR) CALLBACK_NOTIFY_(FOR, p - data)

/* Run data callback FOR with LEN bytes, returning ER if it fails */
#define CALLBACK_DATA_(FOR, LEN, ER)                                         \
    do                                                                       \
    {                                                                        \
        assert(HTTP_PARSER_ERRNO(parser) == HPE_OK);                         \
                                                                             \
        if (FOR##_mark)                                                      \
        {                                                                    \
            if (LIKELY(settings->on_##FOR))                                  \
            {                                                                \
                parser->state = CURRENT_STATE();                             \
                if (UNLIKELY(0 !=                                            \
                             settings->on_##FOR(parser, FOR##_mark, (LEN)))) \
                {                                                            \
                    SET_ERRNO(HPE_CB_##FOR);                                 \
                }                                                            \
                UPDATE_STATE(parser->state);                                 \
                                                                             \
                /* We either errored above or got paused; get out */         \
                if (UNLIKELY(HTTP_PARSER_ERRNO(parser) != HPE_OK))           \
                {                                                            \
                    return (ER);                                             \
                }                                                            \
            }                                                                \
            FOR##_mark = NULL;                                               \
        }                                                                    \
    } while (0)

/* Run the data callback FOR and consume the current byte */
#define CALLBACK_DATA(FOR) \
    CALLBACK_DATA_(FOR, p - FOR##_mark, p - data + 1)

/* Run the data callback FOR and don't consume the current byte */
#define CALLBACK_DATA_NOADVANCE(FOR) \
    CALLBACK_DATA_(FOR, p - FOR##_mark, p - data)

/* Set the mark FOR; non-destructive if mark is already set */
#define MARK(FOR)           \
    do                      \
    {                       \
        if (!FOR##_mark)    \
        {                   \
            FOR##_mark = p; \
        }                   \
    } while (0)

/* Don't allow the total size of the HTTP headers (including the status
 * line) to exceed max_header_size.  This check is here to protect
 * embedders against denial-of-service attacks where the attacker feeds
 * us a never-ending header that the embedder keeps buffering.
 *
 * This check is arguably the responsibility of embedders but we're doing
 * it on the embedder's behalf because most won't bother and this way we
 * make the web a little safer.  max_header_size is still far bigger
 * than any reasonable request or response so this should never affect
 * day-to-day operation.
 */
#define COUNT_HEADER_SIZE(V)                   \
    do                                         \
    {                                          \
        nread += (uint32_t)(V);                \
        if (UNLIKELY(nread > max_header_size)) \
        {                                      \
            SET_ERRNO(HPE_HEADER_OVERFLOW);    \
            goto error;                        \
        }                                      \
    } while (0)

#define PROXY_CONNECTION "proxy-connection"
#define CONNECTION "connection"
#define CONTENT_LENGTH "content-length"
#define TRANSFER_ENCODING "transfer-encoding"
#define UPGRADE "upgrade"
#define CHUNKED "chunked"
#define KEEP_ALIVE "keep-alive"
#define CLOSE "close"

static const char *method_strings[] =
        {
#define XX(num, name, string) #string,
                HTTP_METHOD_MAP(XX)
#undef XX
};

/* Tokens as defined by rfc 2616. Also lowercases them.
 *        token       = 1*<any CHAR except CTLs or separators>
 *     separators     = "(" | ")" | "<" | ">" | "@"
 *                    | "," | ";" | ":" | "\" | <">
 *                    | "/" | "[" | "]" | "?" | "="
 *                    | "{" | "}" | SP | HT
 */
static const char tokens[256] = {
        /*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
        0, 0, 0, 0, 0, 0, 0, 0,
        /*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
        0, 0, 0, 0, 0, 0, 0, 0,
        /*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
        0, 0, 0, 0, 0, 0, 0, 0,
        /*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
        0, 0, 0, 0, 0, 0, 0, 0,
        /*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
        ' ', '!', 0, '#', '$', '%', '&', '\'',
        /*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
        0, 0, '*', '+', 0, '-', '.', 0,
        /*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
        '0', '1', '2', '3', '4', '5', '6', '7',
        /*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
        '8', '9', 0, 0, 0, 0, 0, 0,
        /*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
        0, 'a', 'b', 'c', 'd', 'e', 'f', 'g',
        /*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
        'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
        /*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
        'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
        /*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
        'x', 'y', 'z', 0, 0, 0, '^', '_',
        /*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
        '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
        /* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
        'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
        /* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
        'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
        /* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
        'x', 'y', 'z', 0, '|', 0, '~', 0};

static const int8_t unhex[256] =
        {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};

#if HTTP_PARSER_STRICT
#define T(v) 0
#else
#define T(v) v
#endif

static const uint8_t normal_url_char[32] = {
        /*   0 nul    1 soh    2 stx    3 etx    4 eot    5 enq    6 ack    7 bel  */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*   8 bs     9 ht    10 nl    11 vt    12 np    13 cr    14 so    15 si   */
        0 | T(2) | 0 | 0 | T(16) | 0 | 0 | 0,
        /*  16 dle   17 dc1   18 dc2   19 dc3   20 dc4   21 nak   22 syn   23 etb */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*  24 can   25 em    26 sub   27 esc   28 fs    29 gs    30 rs    31 us  */
        0 | 0 | 0 | 0 | 0 | 0 | 0 | 0,
        /*  32 sp    33  !    34  "    35  #    36  $    37  %    38  &    39  '  */
        0 | 2 | 4 | 0 | 16 | 32 | 64 | 128,
        /*  40  (    41  )    42  *    43  +    44  ,    45  -    46  .    47  /  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  48  0    49  1    50  2    51  3    52  4    53  5    54  6    55  7  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  56  8    57  9    58  :    59  ;    60  <    61  =    62  >    63  ?  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 0,
        /*  64  @    65  A    66  B    67  C    68  D    69  E    70  F    71  G  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  72  H    73  I    74  J    75  K    76  L    77  M    78  N    79  O  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  80  P    81  Q    82  R    83  S    84  T    85  U    86  V    87  W  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  88  X    89  Y    90  Z    91  [    92  \    93  ]    94  ^    95  _  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /*  96  `    97  a    98  b    99  c   100  d   101  e   102  f   103  g  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 104  h   105  i   106  j   107  k   108  l   109  m   110  n   111  o  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 112  p   113  q   114  r   115  s   116  t   117  u   118  v   119  w  */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 128,
        /* 120  x   121  y   122  z   123  {   124  |   125  }   126  ~   127 del */
        1 | 2 | 4 | 8 | 16 | 32 | 64 | 0,
};

#undef T

enum state
{
    s_dead = 1 /* important that this is > 0 */

    ,
    s_start_req_or_res,
    s_res_or_resp_H,
    s_start_res,
    s_res_H,
    s_res_HT,
    s_res_HTT,
    s_res_HTTP,
    s_res_http_major,
    s_res_http_dot,
    s_res_http_minor,
    s_res_http_end,
    s_res_first_status_code,
    s_res_status_code,
    s_res_status_start,
    s_res_status,
    s_res_line_almost_done

    ,
    s_start_req

    ,
    s_req_method,
    s_req_spaces_before_url,
    s_req_schema,
    s_req_schema_slash,
    s_req_schema_slash_slash,
    s_req_server_start,
    s_req_server,
    s_req_server_with_at,
    s_req_path,
    s_req_query_string_start,
    s_req_query_string,
    s_req_fragment_start,
    s_req_fragment,
    s_req_http_start,
    s_req_http_H,
    s_req_http_HT,
    s_req_http_HTT,
    s_req_http_HTTP,
    s_req_http_I,
    s_req_http_IC,
    s_req_http_major,
    s_req_http_dot,
    s_req_http_minor,
    s_req_http_end,
    s_req_line_almost_done

    ,
    s_header_field_start,
    s_header_field,
    s_header_value_discard_ws,
    s_header_value_discard_ws_almost_done,
    s_header_value_discard_lws,
    s_header_value_start,
    s_header_value,
    s_header_value_lws

    ,
    s_header_almost_done

    ,
    s_chunk_size_start,
    s_chunk_size,
    s_chunk_parameters,
    s_chunk_size_almost_done

    ,
    s_headers_almost_done,
    s_headers_done

    /* Important: 's_headers_done' must be the last 'header' state. All
   * states beyond this must be 'body' states. It is used for overflow
   * checking. See the PARSING_HEADER() macro.
   */

    ,
    s_chunk_data,
    s_chunk_data_almost_done,
    s_chunk_data_done

    ,
    s_body_identity,
    s_body_identity_eof

    ,
    s_message_done
};

#define PARSING_HEADER(state) (state <= s_headers_done)

enum header_states
{
    h_general = 0,
    h_C,
    h_CO,
    h_CON

    ,
    h_matching_connection,
    h_matching_proxy_connection,
    h_matching_content_length,
    h_matching_transfer_encoding,
    h_matching_upgrade

    ,
    h_connection,
    h_content_length,
    h_content_length_num,
    h_content_length_ws,
    h_transfer_encoding,
    h_upgrade

    ,
    h_matching_transfer_encoding_chunked,
    h_matching_connection_token_start,
    h_matching_connection_keep_alive,
    h_matching_connection_close,
    h_matching_connection_upgrade,
    h_matching_connection_token

    ,
    h_transfer_encoding_chunked,
    h_connection_keep_alive,
    h_connection_close,
    h_connection_upgrade
};

enum http_host_state
{
    s_http_host_dead = 1,
    s_http_userinfo_start,
    s_http_userinfo,
    s_http_host_start,
    s_http_host_v6_start,
    s_http_host,
    s_http_host_v6,
    s_http_host_v6_end,
    s_http_host_v6_zone_start,
    s_http_host_v6_zone,
    s_http_host_port_start,
    s_http_host_port
};

/* Macros for character classes; depends on strict-mode  */
#define CR '\r'
#define LF '\n'
#define LOWER(c) (unsigned char) (c | 0x20)
#define IS_ALPHA(c) (LOWER(c) >= 'a' && LOWER(c) <= 'z')
#define IS_NUM(c) ((c) >= '0' && (c) <= '9')
#define IS_ALPHANUM(c) (IS_ALPHA(c) || IS_NUM(c))
#define IS_HEX(c) (IS_NUM(c) || (LOWER(c) >= 'a' && LOWER(c) <= 'f'))
#define IS_MARK(c) ((c) == '-' || (c) == '_' || (c) == '.' ||                              \
                    (c) == '!' || (c) == '~' || (c) == '*' || (c) == '\'' || (c) == '(' || \
                    (c) == ')')
#define IS_USERINFO_CHAR(c) (IS_ALPHANUM(c) || IS_MARK(c) || (c) == '%' ||                         \
                             (c) == ';' || (c) == ':' || (c) == '&' || (c) == '=' || (c) == '+' || \
                             (c) == '$' || (c) == ',')

#define STRICT_TOKEN(c) ((c == ' ') ? 0 : tokens[(unsigned char) c])

#if HTTP_PARSER_STRICT
#define TOKEN(c) STRICT_TOKEN(c)
#define IS_URL_CHAR(c) (BIT_AT(normal_url_char, (unsigned char) c))
#define IS_HOST_CHAR(c) (IS_ALPHANUM(c) || (c) == '.' || (c) == '-')
#else
#define TOKEN(c) tokens[(unsigned char) c]
#define IS_URL_CHAR(c) \
    (BIT_AT(normal_url_char, (unsigned char) c) || ((c) &0x80))
#define IS_HOST_CHAR(c) \
    (IS_ALPHANUM(c) || (c) == '.' || (c) == '-' || (c) == '_')
#endif

/**
 * Verify that a char is a valid visible (printable) US-ASCII
 * character or %x80-FF
 **/
#define IS_HEADER_CHAR(ch) \
    (ch == CR || ch == LF || ch == 9 || ((unsigned char) ch > 31 && ch != 127))

#define start_state (parser->type == HTTP_REQUEST ? s_start_req : s_start_res)

#if HTTP_PARSER_STRICT
#define STRICT_CHECK(cond)         \
    do                             \
    {                              \
        if (cond)                  \
        {                          \
            SET_ERRNO(HPE_STRICT); \
            goto error;            \
        }                          \
    } while (0)
#define NEW_MESSAGE() (http_should_keep_alive(parser) ? start_state : s_dead)
#else
#define STRICT_CHECK(cond)
#define NEW_MESSAGE() start_state
#endif

/* Map errno values to strings for human-readable output */
#define HTTP_STRERROR_GEN(n, s) {"HPE_" #n, s},
static struct
{
    const char *name;
    const char *description;
} http_strerror_tab[] = {
        HTTP_ERRNO_MAP(HTTP_STRERROR_GEN)};
#undef HTTP_STRERROR_GEN

static int http_message_needs_eof(const http_parser *parser);

/* Our URL parser.
 *
 * This is designed to be shared by http_parser_execute() for URL validation,
 * hence it has a state transition + byte-for-byte interface. In addition, it
 * is meant to be embedded in http_parser_parse_url(), which does the dirty
 * work of turning state transitions URL components for its API.
 *
 * This function should only be invoked with non-space characters. It is
 * assumed that the caller cares about (and can detect) the transition between
 * URL and non-URL states by looking for these.
 */
static enum state
parse_url_char(enum state s, const char ch)
{
    if (ch == ' ' || ch == '\r' || ch == '\n')
    {
        return s_dead;
    }

#if HTTP_PARSER_STRICT
    if (ch == '\t' || ch == '\f')
    {
        return s_dead;
    }
#endif

    switch (s)
    {
        case s_req_spaces_before_url:
            /* Proxied requests are followed by scheme of an absolute URI (alpha).
       * All methods except CONNECT are followed by '/' or '*'.
       */

            if (ch == '/' || ch == '*')
            {
                return s_req_path;
            }

            if (IS_ALPHA(ch))
            {
                return s_req_schema;
            }

            break;

        case s_req_schema:
            if (IS_ALPHA(ch))
            {
                return s;
            }

            if (ch == ':')
            {
                return s_req_schema_slash;
            }

            break;

        case s_req_schema_slash:
            if (ch == '/')
            {
                return s_req_schema_slash_slash;
            }

            break;

        case s_req_schema_slash_slash:
            if (ch == '/')
            {
                return s_req_server_start;
            }

            break;

        case s_req_server_with_at:
            if (ch == '@')
            {
                return s_dead;
            }

        /* fall through */
        case s_req_server_start:
        case s_req_server:
            if (ch == '/')
            {
                return s_req_path;
            }

            if (ch == '?')
            {
                return s_req_query_string_start;
            }

            if (ch == '@')
            {
                return s_req_server_with_at;
            }

            if (IS_USERINFO_CHAR(ch) || ch == '[' || ch == ']')
            {
                return s_req_server;
            }

            break;

        case s_req_path:
            if (IS_URL_CHAR(ch))
            {
                return s;
            }

            switch (ch)
            {
                case '?':
                    return s_req_query_string_start;

                case '#':
                    return s_req_fragment_start;
            }

            break;

        case s_req_query_string_start:
        case s_req_query_string:
            if (IS_URL_CHAR(ch))
            {
                return s_req_query_string;
            }

            switch (ch)
            {
                case '?':
                    /* allow extra '?' in query string */
                    return s_req_query_string;

                case '#':
                    return s_req_fragment_start;
            }

            break;

        case s_req_fragment_start:
            if (IS_URL_CHAR(ch))
            {
                return s_req_fragment;
            }

            switch (ch)
            {
                case '?':
                    return s_req_fragment;

                case '#':
                    return s;
            }

            break;

        case s_req_fragment:
            if (IS_URL_CHAR(ch))
            {
                return s;
            }

            switch (ch)
            {
                case '?':
                case '#':
                    return s;
            }

            break;

        default:
            break;
    }

    /* We should never fall out of the switch above unless there's an error */
    return s_dead;
}

static size_t http_parser_execute(http_parser *parser,
                                  const http_parser_settings *settings,
                                  const char *data,
                                  size_t len)
{
    char c, ch;
    int8_t unhex_val;
    const char *p = data;
    const char *header_field_mark = 0;
    const char *header_value_mark = 0;
    const char *url_mark = 0;
    const char *body_mark = 0;
    const char *status_mark = 0;
    enum state p_state = (enum state) parser->state;
    const unsigned int lenient = parser->lenient_http_headers;
    uint32_t nread = parser->nread;

    /* We're in an error state. Don't bother doing anything. */
    if (HTTP_PARSER_ERRNO(parser) != HPE_OK)
    {
        return 0;
    }

    if (len == 0)
    {
        switch (CURRENT_STATE())
        {
            case s_body_identity_eof:
                /* Use of CALLBACK_NOTIFY() here would erroneously return 1 byte read if
         * we got paused.
         */
                CALLBACK_NOTIFY_NOADVANCE(message_complete);
                return 0;

            case s_dead:
            case s_start_req_or_res:
            case s_start_res:
            case s_start_req:
                return 0;

            default:
                SET_ERRNO(HPE_INVALID_EOF_STATE);
                return 1;
        }
    }

    if (CURRENT_STATE() == s_header_field)
        header_field_mark = data;
    if (CURRENT_STATE() == s_header_value)
        header_value_mark = data;
    switch (CURRENT_STATE())
    {
        case s_req_path:
        case s_req_schema:
        case s_req_schema_slash:
        case s_req_schema_slash_slash:
        case s_req_server_start:
        case s_req_server:
        case s_req_server_with_at:
        case s_req_query_string_start:
        case s_req_query_string:
        case s_req_fragment_start:
        case s_req_fragment:
            url_mark = data;
            break;
        case s_res_status:
            status_mark = data;
            break;
        default:
            break;
    }

    for (p = data; p != data + len; p++)
    {
        ch = *p;

        if (PARSING_HEADER(CURRENT_STATE()))
            COUNT_HEADER_SIZE(1);

    reexecute:
        switch (CURRENT_STATE())
        {

            case s_dead:
                /* this state is used after a 'Connection: close' message
         * the parser will error out if it reads another message
         */
                if (LIKELY(ch == CR || ch == LF))
                    break;

                SET_ERRNO(HPE_CLOSED_CONNECTION);
                goto error;

            case s_start_req_or_res:
            {
                if (ch == CR || ch == LF)
                    break;
                parser->flags = 0;
                parser->content_length = ULLONG_MAX;

                if (ch == 'H')
                {
                    UPDATE_STATE(s_res_or_resp_H);

                    CALLBACK_NOTIFY(message_begin);
                }
                else
                {
                    parser->type = HTTP_REQUEST;
                    UPDATE_STATE(s_start_req);
                    REEXECUTE();
                }

                break;
            }

            case s_res_or_resp_H:
                if (ch == 'T')
                {
                    parser->type = HTTP_RESPONSE;
                    UPDATE_STATE(s_res_HT);
                }
                else
                {
                    if (UNLIKELY(ch != 'E'))
                    {
                        SET_ERRNO(HPE_INVALID_CONSTANT);
                        goto error;
                    }

                    parser->type = HTTP_REQUEST;
                    parser->method = HTTP_HEAD;
                    parser->index = 2;
                    UPDATE_STATE(s_req_method);
                }
                break;

            case s_start_res:
            {
                if (ch == CR || ch == LF)
                    break;
                parser->flags = 0;
                parser->content_length = ULLONG_MAX;

                if (ch == 'H')
                {
                    UPDATE_STATE(s_res_H);
                }
                else
                {
                    SET_ERRNO(HPE_INVALID_CONSTANT);
                    goto error;
                }

                CALLBACK_NOTIFY(message_begin);
                break;
            }

            case s_res_H:
                STRICT_CHECK(ch != 'T');
                UPDATE_STATE(s_res_HT);
                break;

            case s_res_HT:
                STRICT_CHECK(ch != 'T');
                UPDATE_STATE(s_res_HTT);
                break;

            case s_res_HTT:
                STRICT_CHECK(ch != 'P');
                UPDATE_STATE(s_res_HTTP);
                break;

            case s_res_HTTP:
                STRICT_CHECK(ch != '/');
                UPDATE_STATE(s_res_http_major);
                break;

            case s_res_http_major:
                if (UNLIKELY(!IS_NUM(ch)))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                parser->http_major = ch - '0';
                UPDATE_STATE(s_res_http_dot);
                break;

            case s_res_http_dot:
            {
                if (UNLIKELY(ch != '.'))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                UPDATE_STATE(s_res_http_minor);
                break;
            }

            case s_res_http_minor:
                if (UNLIKELY(!IS_NUM(ch)))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                parser->http_minor = ch - '0';
                UPDATE_STATE(s_res_http_end);
                break;

            case s_res_http_end:
            {
                if (UNLIKELY(ch != ' '))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                UPDATE_STATE(s_res_first_status_code);
                break;
            }

            case s_res_first_status_code:
            {
                if (!IS_NUM(ch))
                {
                    if (ch == ' ')
                    {
                        break;
                    }

                    SET_ERRNO(HPE_INVALID_STATUS);
                    goto error;
                }
                parser->status_code = ch - '0';
                UPDATE_STATE(s_res_status_code);
                break;
            }

            case s_res_status_code:
            {
                if (!IS_NUM(ch))
                {
                    switch (ch)
                    {
                        case ' ':
                            UPDATE_STATE(s_res_status_start);
                            break;
                        case CR:
                        case LF:
                            UPDATE_STATE(s_res_status_start);
                            REEXECUTE();
                            break;
                        default:
                            SET_ERRNO(HPE_INVALID_STATUS);
                            goto error;
                    }
                    break;
                }

                parser->status_code *= 10;
                parser->status_code += ch - '0';

                if (UNLIKELY(parser->status_code > 999))
                {
                    SET_ERRNO(HPE_INVALID_STATUS);
                    goto error;
                }

                break;
            }

            case s_res_status_start:
            {
                MARK(status);
                UPDATE_STATE(s_res_status);
                parser->index = 0;

                if (ch == CR || ch == LF)
                    REEXECUTE();

                break;
            }

            case s_res_status:
                if (ch == CR)
                {
                    UPDATE_STATE(s_res_line_almost_done);
                    CALLBACK_DATA(status);
                    break;
                }

                if (ch == LF)
                {
                    UPDATE_STATE(s_header_field_start);
                    CALLBACK_DATA(status);
                    break;
                }

                break;

            case s_res_line_almost_done:
                STRICT_CHECK(ch != LF);
                UPDATE_STATE(s_header_field_start);
                break;

            case s_start_req:
            {
                if (ch == CR || ch == LF)
                    break;
                parser->flags = 0;
                parser->content_length = ULLONG_MAX;

                if (UNLIKELY(!IS_ALPHA(ch)))
                {
                    SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }

                parser->method = (enum http_method) 0;
                parser->index = 1;
                switch (ch)
                {
                    case 'A':
                        parser->method = HTTP_ACL;
                        break;
                    case 'B':
                        parser->method = HTTP_BIND;
                        break;
                    case 'C':
                        parser->method = HTTP_CONNECT; /* or COPY, CHECKOUT */
                        break;
                    case 'D':
                        parser->method = HTTP_DELETE;
                        break;
                    case 'G':
                        parser->method = HTTP_GET;
                        break;
                    case 'H':
                        parser->method = HTTP_HEAD;
                        break;
                    case 'L':
                        parser->method = HTTP_LOCK; /* or LINK */
                        break;
                    case 'M':
                        parser->method = HTTP_MKCOL; /* or MOVE, MKACTIVITY, MERGE, M-SEARCH, MKCALENDAR */
                        break;
                    case 'N':
                        parser->method = HTTP_NOTIFY;
                        break;
                    case 'O':
                        parser->method = HTTP_OPTIONS;
                        break;
                    case 'P':
                        parser->method = HTTP_POST;
                        /* or PROPFIND|PROPPATCH|PUT|PATCH|PURGE */
                        break;
                    case 'R':
                        parser->method = HTTP_REPORT; /* or REBIND */
                        break;
                    case 'S':
                        parser->method = HTTP_SUBSCRIBE; /* or SEARCH, SOURCE */
                        break;
                    case 'T':
                        parser->method = HTTP_TRACE;
                        break;
                    case 'U':
                        parser->method = HTTP_UNLOCK; /* or UNSUBSCRIBE, UNBIND, UNLINK */
                        break;
                    default:
                        SET_ERRNO(HPE_INVALID_METHOD);
                        goto error;
                }
                UPDATE_STATE(s_req_method);

                CALLBACK_NOTIFY(message_begin);

                break;
            }

            case s_req_method:
            {
                const char *matcher;
                if (UNLIKELY(ch == '\0'))
                {
                    SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }

                matcher = method_strings[parser->method];
                if (ch == ' ' && matcher[parser->index] == '\0')
                {
                    UPDATE_STATE(s_req_spaces_before_url);
                }
                else if (ch == matcher[parser->index])
                {
                    ; /* nada */
                }
                else if ((ch >= 'A' && ch <= 'Z') || ch == '-')
                {

                    switch (parser->method << 16 | parser->index << 8 | ch)
                    {
#define XX(meth, pos, ch, new_meth)           \
    case (HTTP_##meth << 16 | pos << 8 | ch): \
        parser->method = HTTP_##new_meth;     \
        break;

                        XX(POST, 1, 'U', PUT)
                        XX(POST, 1, 'A', PATCH)
                        XX(POST, 1, 'R', PROPFIND)
                        XX(PUT, 2, 'R', PURGE)
                        XX(CONNECT, 1, 'H', CHECKOUT)
                        XX(CONNECT, 2, 'P', COPY)
                        XX(MKCOL, 1, 'O', MOVE)
                        XX(MKCOL, 1, 'E', MERGE)
                        XX(MKCOL, 1, '-', MSEARCH)
                        XX(MKCOL, 2, 'A', MKACTIVITY)
                        XX(MKCOL, 3, 'A', MKCALENDAR)
                        XX(SUBSCRIBE, 1, 'E', SEARCH)
                        XX(SUBSCRIBE, 1, 'O', SOURCE)
                        XX(REPORT, 2, 'B', REBIND)
                        XX(PROPFIND, 4, 'P', PROPPATCH)
                        XX(LOCK, 1, 'I', LINK)
                        XX(UNLOCK, 2, 'S', UNSUBSCRIBE)
                        XX(UNLOCK, 2, 'B', UNBIND)
                        XX(UNLOCK, 3, 'I', UNLINK)
#undef XX
                        default:
                            SET_ERRNO(HPE_INVALID_METHOD);
                            goto error;
                    }
                }
                else
                {
                    SET_ERRNO(HPE_INVALID_METHOD);
                    goto error;
                }

                ++parser->index;
                break;
            }

            case s_req_spaces_before_url:
            {
                if (ch == ' ')
                    break;

                MARK(url);
                if (parser->method == HTTP_CONNECT)
                {
                    UPDATE_STATE(s_req_server_start);
                }

                UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
                if (UNLIKELY(CURRENT_STATE() == s_dead))
                {
                    SET_ERRNO(HPE_INVALID_URL);
                    goto error;
                }

                break;
            }

            case s_req_schema:
            case s_req_schema_slash:
            case s_req_schema_slash_slash:
            case s_req_server_start:
            {
                switch (ch)
                {
                    /* No whitespace allowed here */
                    case ' ':
                    case CR:
                    case LF:
                        SET_ERRNO(HPE_INVALID_URL);
                        goto error;
                    default:
                        UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
                        if (UNLIKELY(CURRENT_STATE() == s_dead))
                        {
                            SET_ERRNO(HPE_INVALID_URL);
                            goto error;
                        }
                }

                break;
            }

            case s_req_server:
            case s_req_server_with_at:
            case s_req_path:
            case s_req_query_string_start:
            case s_req_query_string:
            case s_req_fragment_start:
            case s_req_fragment:
            {
                switch (ch)
                {
                    case ' ':
                        UPDATE_STATE(s_req_http_start);
                        CALLBACK_DATA(url);
                        break;
                    case CR:
                    case LF:
                        parser->http_major = 0;
                        parser->http_minor = 9;
                        UPDATE_STATE((ch == CR) ? s_req_line_almost_done : s_header_field_start);
                        CALLBACK_DATA(url);
                        break;
                    default:
                        UPDATE_STATE(parse_url_char(CURRENT_STATE(), ch));
                        if (UNLIKELY(CURRENT_STATE() == s_dead))
                        {
                            SET_ERRNO(HPE_INVALID_URL);
                            goto error;
                        }
                }
                break;
            }

            case s_req_http_start:
                switch (ch)
                {
                    case ' ':
                        break;
                    case 'H':
                        UPDATE_STATE(s_req_http_H);
                        break;
                    case 'I':
                        if (parser->method == HTTP_SOURCE)
                        {
                            UPDATE_STATE(s_req_http_I);
                            break;
                        }
                        /* fall through */
                    default:
                        SET_ERRNO(HPE_INVALID_CONSTANT);
                        goto error;
                }
                break;

            case s_req_http_H:
                STRICT_CHECK(ch != 'T');
                UPDATE_STATE(s_req_http_HT);
                break;

            case s_req_http_HT:
                STRICT_CHECK(ch != 'T');
                UPDATE_STATE(s_req_http_HTT);
                break;

            case s_req_http_HTT:
                STRICT_CHECK(ch != 'P');
                UPDATE_STATE(s_req_http_HTTP);
                break;

            case s_req_http_I:
                STRICT_CHECK(ch != 'C');
                UPDATE_STATE(s_req_http_IC);
                break;

            case s_req_http_IC:
                STRICT_CHECK(ch != 'E');
                UPDATE_STATE(s_req_http_HTTP); /* Treat "ICE" as "HTTP". */
                break;

            case s_req_http_HTTP:
                STRICT_CHECK(ch != '/');
                UPDATE_STATE(s_req_http_major);
                break;

            case s_req_http_major:
                if (UNLIKELY(!IS_NUM(ch)))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                parser->http_major = ch - '0';
                UPDATE_STATE(s_req_http_dot);
                break;

            case s_req_http_dot:
            {
                if (UNLIKELY(ch != '.'))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                UPDATE_STATE(s_req_http_minor);
                break;
            }

            case s_req_http_minor:
                if (UNLIKELY(!IS_NUM(ch)))
                {
                    SET_ERRNO(HPE_INVALID_VERSION);
                    goto error;
                }

                parser->http_minor = ch - '0';
                UPDATE_STATE(s_req_http_end);
                break;

            case s_req_http_end:
            {
                if (ch == CR)
                {
                    UPDATE_STATE(s_req_line_almost_done);
                    break;
                }

                if (ch == LF)
                {
                    UPDATE_STATE(s_header_field_start);
                    break;
                }

                SET_ERRNO(HPE_INVALID_VERSION);
                goto error;
                break;
            }

            /* end of request line */
            case s_req_line_almost_done:
            {
                if (UNLIKELY(ch != LF))
                {
                    SET_ERRNO(HPE_LF_EXPECTED);
                    goto error;
                }

                UPDATE_STATE(s_header_field_start);
                break;
            }

            case s_header_field_start:
            {
                if (ch == CR)
                {
                    UPDATE_STATE(s_headers_almost_done);
                    break;
                }

                if (ch == LF)
                {
                    /* they might be just sending \n instead of \r\n so this would be
           * the second \n to denote the end of headers*/
                    UPDATE_STATE(s_headers_almost_done);
                    REEXECUTE();
                }

                c = TOKEN(ch);

                if (UNLIKELY(!c))
                {
                    SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
                    goto error;
                }

                MARK(header_field);

                parser->index = 0;
                UPDATE_STATE(s_header_field);

                switch (c)
                {
                    case 'c':
                        parser->header_state = h_C;
                        break;

                    case 'p':
                        parser->header_state = h_matching_proxy_connection;
                        break;

                    case 't':
                        parser->header_state = h_matching_transfer_encoding;
                        break;

                    case 'u':
                        parser->header_state = h_matching_upgrade;
                        break;

                    default:
                        parser->header_state = h_general;
                        break;
                }
                break;
            }

            case s_header_field:
            {
                const char *start = p;
                for (; p != data + len; p++)
                {
                    ch = *p;
                    c = TOKEN(ch);

                    if (!c)
                        break;

                    switch (parser->header_state)
                    {
                        case h_general:
                        {
                            size_t left = data + len - p;
                            const char *pe = p + MIN(left, max_header_size);
                            while (p + 1 < pe && TOKEN(p[1]))
                            {
                                p++;
                            }
                            break;
                        }

                        case h_C:
                            parser->index++;
                            parser->header_state = (c == 'o' ? h_CO : h_general);
                            break;

                        case h_CO:
                            parser->index++;
                            parser->header_state = (c == 'n' ? h_CON : h_general);
                            break;

                        case h_CON:
                            parser->index++;
                            switch (c)
                            {
                                case 'n':
                                    parser->header_state = h_matching_connection;
                                    break;
                                case 't':
                                    parser->header_state = h_matching_content_length;
                                    break;
                                default:
                                    parser->header_state = h_general;
                                    break;
                            }
                            break;

                            /* connection */

                        case h_matching_connection:
                            parser->index++;
                            if (parser->index > sizeof(CONNECTION) - 1 || c != CONNECTION[parser->index])
                            {
                                parser->header_state = h_general;
                            }
                            else if (parser->index == sizeof(CONNECTION) - 2)
                            {
                                parser->header_state = h_connection;
                            }
                            break;

                            /* proxy-connection */

                        case h_matching_proxy_connection:
                            parser->index++;
                            if (parser->index > sizeof(PROXY_CONNECTION) - 1 || c != PROXY_CONNECTION[parser->index])
                            {
                                parser->header_state = h_general;
                            }
                            else if (parser->index == sizeof(PROXY_CONNECTION) - 2)
                            {
                                parser->header_state = h_connection;
                            }
                            break;

                            /* content-length */

                        case h_matching_content_length:
                            parser->index++;
                            if (parser->index > sizeof(CONTENT_LENGTH) - 1 || c != CONTENT_LENGTH[parser->index])
                            {
                                parser->header_state = h_general;
                            }
                            else if (parser->index == sizeof(CONTENT_LENGTH) - 2)
                            {
                                parser->header_state = h_content_length;
                            }
                            break;

                            /* transfer-encoding */

                        case h_matching_transfer_encoding:
                            parser->index++;
                            if (parser->index > sizeof(TRANSFER_ENCODING) - 1 || c != TRANSFER_ENCODING[parser->index])
                            {
                                parser->header_state = h_general;
                            }
                            else if (parser->index == sizeof(TRANSFER_ENCODING) - 2)
                            {
                                parser->header_state = h_transfer_encoding;
                            }
                            break;

                            /* upgrade */

                        case h_matching_upgrade:
                            parser->index++;
                            if (parser->index > sizeof(UPGRADE) - 1 || c != UPGRADE[parser->index])
                            {
                                parser->header_state = h_general;
                            }
                            else if (parser->index == sizeof(UPGRADE) - 2)
                            {
                                parser->header_state = h_upgrade;
                            }
                            break;

                        case h_connection:
                        case h_content_length:
                        case h_transfer_encoding:
                        case h_upgrade:
                            if (ch != ' ')
                                parser->header_state = h_general;
                            break;

                        default:
                            assert(0 && "Unknown header_state");
                            break;
                    }
                }

                if (p == data + len)
                {
                    --p;
                    COUNT_HEADER_SIZE(p - start);
                    break;
                }

                COUNT_HEADER_SIZE(p - start);

                if (ch == ':')
                {
                    UPDATE_STATE(s_header_value_discard_ws);
                    CALLBACK_DATA(header_field);
                    break;
                }

                SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
                goto error;
            }

            case s_header_value_discard_ws:
                if (ch == ' ' || ch == '\t')
                    break;

                if (ch == CR)
                {
                    UPDATE_STATE(s_header_value_discard_ws_almost_done);
                    break;
                }

                if (ch == LF)
                {
                    UPDATE_STATE(s_header_value_discard_lws);
                    break;
                }

                /* fall through */

            case s_header_value_start:
            {
                MARK(header_value);

                UPDATE_STATE(s_header_value);
                parser->index = 0;

                c = LOWER(ch);

                switch (parser->header_state)
                {
                    case h_upgrade:
                        parser->flags |= F_UPGRADE;
                        parser->header_state = h_general;
                        break;

                    case h_transfer_encoding:
                        /* looking for 'Transfer-Encoding: chunked' */
                        if ('c' == c)
                        {
                            parser->header_state = h_matching_transfer_encoding_chunked;
                        }
                        else
                        {
                            parser->header_state = h_general;
                        }
                        break;

                    case h_content_length:
                        if (UNLIKELY(!IS_NUM(ch)))
                        {
                            SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                            goto error;
                        }

                        if (parser->flags & F_CONTENTLENGTH)
                        {
                            SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH);
                            goto error;
                        }

                        parser->flags |= F_CONTENTLENGTH;
                        parser->content_length = ch - '0';
                        parser->header_state = h_content_length_num;
                        break;

                    /* when obsolete line folding is encountered for content length
           * continue to the s_header_value state */
                    case h_content_length_ws:
                        break;

                    case h_connection:
                        /* looking for 'Connection: keep-alive' */
                        if (c == 'k')
                        {
                            parser->header_state = h_matching_connection_keep_alive;
                            /* looking for 'Connection: close' */
                        }
                        else if (c == 'c')
                        {
                            parser->header_state = h_matching_connection_close;
                        }
                        else if (c == 'u')
                        {
                            parser->header_state = h_matching_connection_upgrade;
                        }
                        else
                        {
                            parser->header_state = h_matching_connection_token;
                        }
                        break;

                    /* Multi-value `Connection` header */
                    case h_matching_connection_token_start:
                        break;

                    default:
                        parser->header_state = h_general;
                        break;
                }
                break;
            }

            case s_header_value:
            {
                const char *start = p;
                enum header_states h_state = (enum header_states) parser->header_state;
                for (; p != data + len; p++)
                {
                    ch = *p;
                    if (ch == CR)
                    {
                        UPDATE_STATE(s_header_almost_done);
                        parser->header_state = h_state;
                        CALLBACK_DATA(header_value);
                        break;
                    }

                    if (ch == LF)
                    {
                        UPDATE_STATE(s_header_almost_done);
                        COUNT_HEADER_SIZE(p - start);
                        parser->header_state = h_state;
                        CALLBACK_DATA_NOADVANCE(header_value);
                        REEXECUTE();
                    }

                    if (!lenient && !IS_HEADER_CHAR(ch))
                    {
                        SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
                        goto error;
                    }

                    c = LOWER(ch);

                    switch (h_state)
                    {
                        case h_general:
                        {
                            size_t left = data + len - p;
                            const char *pe = p + MIN(left, max_header_size);

                            for (; p != pe; p++)
                            {
                                ch = *p;
                                if (ch == CR || ch == LF)
                                {
                                    --p;
                                    break;
                                }
                                if (!lenient && !IS_HEADER_CHAR(ch))
                                {
                                    SET_ERRNO(HPE_INVALID_HEADER_TOKEN);
                                    goto error;
                                }
                            }
                            if (p == data + len)
                                --p;
                            break;
                        }

                        case h_connection:
                        case h_transfer_encoding:
                            assert(0 && "Shouldn't get here.");
                            break;

                        case h_content_length:
                            if (ch == ' ')
                                break;
                            h_state = h_content_length_num;
                            /* fall through */

                        case h_content_length_num:
                        {
                            uint64_t t;

                            if (ch == ' ')
                            {
                                h_state = h_content_length_ws;
                                break;
                            }

                            if (UNLIKELY(!IS_NUM(ch)))
                            {
                                SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                                parser->header_state = h_state;
                                goto error;
                            }

                            t = parser->content_length;
                            t *= 10;
                            t += ch - '0';

                            /* Overflow? Test against a conservative limit for simplicity. */
                            if (UNLIKELY((ULLONG_MAX - 10) / 10 < parser->content_length))
                            {
                                SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                                parser->header_state = h_state;
                                goto error;
                            }

                            parser->content_length = t;
                            break;
                        }

                        case h_content_length_ws:
                            if (ch == ' ')
                                break;
                            SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                            parser->header_state = h_state;
                            goto error;

                        /* Transfer-Encoding: chunked */
                        case h_matching_transfer_encoding_chunked:
                            parser->index++;
                            if (parser->index > sizeof(CHUNKED) - 1 || c != CHUNKED[parser->index])
                            {
                                h_state = h_general;
                            }
                            else if (parser->index == sizeof(CHUNKED) - 2)
                            {
                                h_state = h_transfer_encoding_chunked;
                            }
                            break;

                        case h_matching_connection_token_start:
                            /* looking for 'Connection: keep-alive' */
                            if (c == 'k')
                            {
                                h_state = h_matching_connection_keep_alive;
                                /* looking for 'Connection: close' */
                            }
                            else if (c == 'c')
                            {
                                h_state = h_matching_connection_close;
                            }
                            else if (c == 'u')
                            {
                                h_state = h_matching_connection_upgrade;
                            }
                            else if (STRICT_TOKEN(c))
                            {
                                h_state = h_matching_connection_token;
                            }
                            else if (c == ' ' || c == '\t')
                            {
                                /* Skip lws */
                            }
                            else
                            {
                                h_state = h_general;
                            }
                            break;

                        /* looking for 'Connection: keep-alive' */
                        case h_matching_connection_keep_alive:
                            parser->index++;
                            if (parser->index > sizeof(KEEP_ALIVE) - 1 || c != KEEP_ALIVE[parser->index])
                            {
                                h_state = h_matching_connection_token;
                            }
                            else if (parser->index == sizeof(KEEP_ALIVE) - 2)
                            {
                                h_state = h_connection_keep_alive;
                            }
                            break;

                        /* looking for 'Connection: close' */
                        case h_matching_connection_close:
                            parser->index++;
                            if (parser->index > sizeof(CLOSE) - 1 || c != CLOSE[parser->index])
                            {
                                h_state = h_matching_connection_token;
                            }
                            else if (parser->index == sizeof(CLOSE) - 2)
                            {
                                h_state = h_connection_close;
                            }
                            break;

                        /* looking for 'Connection: upgrade' */
                        case h_matching_connection_upgrade:
                            parser->index++;
                            if (parser->index > sizeof(UPGRADE) - 1 ||
                                c != UPGRADE[parser->index])
                            {
                                h_state = h_matching_connection_token;
                            }
                            else if (parser->index == sizeof(UPGRADE) - 2)
                            {
                                h_state = h_connection_upgrade;
                            }
                            break;

                        case h_matching_connection_token:
                            if (ch == ',')
                            {
                                h_state = h_matching_connection_token_start;
                                parser->index = 0;
                            }
                            break;

                        case h_transfer_encoding_chunked:
                            if (ch != ' ')
                                h_state = h_general;
                            break;

                        case h_connection_keep_alive:
                        case h_connection_close:
                        case h_connection_upgrade:
                            if (ch == ',')
                            {
                                if (h_state == h_connection_keep_alive)
                                {
                                    parser->flags |= F_CONNECTION_KEEP_ALIVE;
                                }
                                else if (h_state == h_connection_close)
                                {
                                    parser->flags |= F_CONNECTION_CLOSE;
                                }
                                else if (h_state == h_connection_upgrade)
                                {
                                    parser->flags |= F_CONNECTION_UPGRADE;
                                }
                                h_state = h_matching_connection_token_start;
                                parser->index = 0;
                            }
                            else if (ch != ' ')
                            {
                                h_state = h_matching_connection_token;
                            }
                            break;

                        default:
                            UPDATE_STATE(s_header_value);
                            h_state = h_general;
                            break;
                    }
                }
                parser->header_state = h_state;

                if (p == data + len)
                    --p;

                COUNT_HEADER_SIZE(p - start);
                break;
            }

            case s_header_almost_done:
            {
                if (UNLIKELY(ch != LF))
                {
                    SET_ERRNO(HPE_LF_EXPECTED);
                    goto error;
                }

                UPDATE_STATE(s_header_value_lws);
                break;
            }

            case s_header_value_lws:
            {
                if (ch == ' ' || ch == '\t')
                {
                    if (parser->header_state == h_content_length_num)
                    {
                        /* treat obsolete line folding as space */
                        parser->header_state = h_content_length_ws;
                    }
                    UPDATE_STATE(s_header_value_start);
                    REEXECUTE();
                }

                /* finished the header */
                switch (parser->header_state)
                {
                    case h_connection_keep_alive:
                        parser->flags |= F_CONNECTION_KEEP_ALIVE;
                        break;
                    case h_connection_close:
                        parser->flags |= F_CONNECTION_CLOSE;
                        break;
                    case h_transfer_encoding_chunked:
                        parser->flags |= F_CHUNKED;
                        break;
                    case h_connection_upgrade:
                        parser->flags |= F_CONNECTION_UPGRADE;
                        break;
                    default:
                        break;
                }

                UPDATE_STATE(s_header_field_start);
                REEXECUTE();
            }

            case s_header_value_discard_ws_almost_done:
            {
                STRICT_CHECK(ch != LF);
                UPDATE_STATE(s_header_value_discard_lws);
                break;
            }

            case s_header_value_discard_lws:
            {
                if (ch == ' ' || ch == '\t')
                {
                    UPDATE_STATE(s_header_value_discard_ws);
                    break;
                }
                else
                {
                    switch (parser->header_state)
                    {
                        case h_connection_keep_alive:
                            parser->flags |= F_CONNECTION_KEEP_ALIVE;
                            break;
                        case h_connection_close:
                            parser->flags |= F_CONNECTION_CLOSE;
                            break;
                        case h_connection_upgrade:
                            parser->flags |= F_CONNECTION_UPGRADE;
                            break;
                        case h_transfer_encoding_chunked:
                            parser->flags |= F_CHUNKED;
                            break;
                        case h_content_length:
                            /* do not allow empty content length */
                            SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                            goto error;
                            break;
                        default:
                            break;
                    }

                    /* header value was empty */
                    MARK(header_value);
                    UPDATE_STATE(s_header_field_start);
                    CALLBACK_DATA_NOADVANCE(header_value);
                    REEXECUTE();
                }
            }

            case s_headers_almost_done:
            {
                STRICT_CHECK(ch != LF);

                if (parser->flags & F_TRAILING)
                {
                    /* End of a chunked request */
                    UPDATE_STATE(s_message_done);
                    CALLBACK_NOTIFY_NOADVANCE(chunk_complete);
                    REEXECUTE();
                }

                /* Cannot use chunked encoding and a content-length header together
           per the HTTP specification. */
                if ((parser->flags & F_CHUNKED) &&
                    (parser->flags & F_CONTENTLENGTH))
                {
                    SET_ERRNO(HPE_UNEXPECTED_CONTENT_LENGTH);
                    goto error;
                }

                UPDATE_STATE(s_headers_done);

                /* Set this here so that on_headers_complete() callbacks can see it */
                if ((parser->flags & F_UPGRADE) &&
                    (parser->flags & F_CONNECTION_UPGRADE))
                {
                    /* For responses, "Upgrade: foo" and "Connection: upgrade" are
           * mandatory only when it is a 101 Switching Protocols response,
           * otherwise it is purely informational, to announce support.
           */
                    parser->upgrade =
                            (parser->type == HTTP_REQUEST || parser->status_code == 101);
                }
                else
                {
                    parser->upgrade = (parser->method == HTTP_CONNECT);
                }

                /* Here we call the headers_complete callback. This is somewhat
         * different than other callbacks because if the user returns 1, we
         * will interpret that as saying that this message has no body. This
         * is needed for the annoying case of recieving a response to a HEAD
         * request.
         *
         * We'd like to use CALLBACK_NOTIFY_NOADVANCE() here but we cannot, so
         * we have to simulate it by handling a change in errno below.
         */
                if (settings->on_headers_complete)
                {
                    switch (settings->on_headers_complete(parser))
                    {
                        case 0:
                            break;

                        case 2:
                            parser->upgrade = 1;

                            /* fall through */
                        case 1:
                            parser->flags |= F_SKIPBODY;
                            break;

                        default:
                            SET_ERRNO(HPE_CB_headers_complete);
                            RETURN(p - data); /* Error */
                    }
                }

                if (HTTP_PARSER_ERRNO(parser) != HPE_OK)
                {
                    RETURN(p - data);
                }

                REEXECUTE();
            }

            case s_headers_done:
            {
                int hasBody;
                STRICT_CHECK(ch != LF);

                parser->nread = 0;
                nread = 0;

                hasBody = parser->flags & F_CHUNKED ||
                          (parser->content_length > 0 && parser->content_length != ULLONG_MAX);
                if (parser->upgrade && (parser->method == HTTP_CONNECT ||
                                        (parser->flags & F_SKIPBODY) || !hasBody))
                {
                    /* Exit, the rest of the message is in a different protocol. */
                    UPDATE_STATE(NEW_MESSAGE());
                    CALLBACK_NOTIFY(message_complete);
                    RETURN((p - data) + 1);
                }

                if (parser->flags & F_SKIPBODY)
                {
                    UPDATE_STATE(NEW_MESSAGE());
                    CALLBACK_NOTIFY(message_complete);
                }
                else if (parser->flags & F_CHUNKED)
                {
                    /* chunked encoding - ignore Content-Length header */
                    UPDATE_STATE(s_chunk_size_start);
                }
                else
                {
                    if (parser->content_length == 0)
                    {
                        /* Content-Length header given but zero: Content-Length: 0\r\n */
                        UPDATE_STATE(NEW_MESSAGE());
                        CALLBACK_NOTIFY(message_complete);
                    }
                    else if (parser->content_length != ULLONG_MAX)
                    {
                        /* Content-Length header given and non-zero */
                        UPDATE_STATE(s_body_identity);
                    }
                    else
                    {
                        if (!http_message_needs_eof(parser))
                        {
                            /* Assume content-length 0 - read the next */
                            UPDATE_STATE(NEW_MESSAGE());
                            CALLBACK_NOTIFY(message_complete);
                        }
                        else
                        {
                            /* Read body until EOF */
                            UPDATE_STATE(s_body_identity_eof);
                        }
                    }
                }

                break;
            }

            case s_body_identity:
            {
                uint64_t to_read = MIN(parser->content_length,
                                       (uint64_t)((data + len) - p));

                assert(parser->content_length != 0 && parser->content_length != ULLONG_MAX);

                /* The difference between advancing content_length and p is because
         * the latter will automaticaly advance on the next loop iteration.
         * Further, if content_length ends up at 0, we want to see the last
         * byte again for our message complete callback.
         */
                MARK(body);
                parser->content_length -= to_read;
                p += to_read - 1;

                if (parser->content_length == 0)
                {
                    UPDATE_STATE(s_message_done);

                    /* Mimic CALLBACK_DATA_NOADVANCE() but with one extra byte.
           *
           * The alternative to doing this is to wait for the next byte to
           * trigger the data callback, just as in every other case. The
           * problem with this is that this makes it difficult for the test
           * harness to distinguish between complete-on-EOF and
           * complete-on-length. It's not clear that this distinction is
           * important for applications, but let's keep it for now.
           */
                    CALLBACK_DATA_(body, p - body_mark + 1, p - data);
                    REEXECUTE();
                }

                break;
            }

            /* read until EOF */
            case s_body_identity_eof:
                MARK(body);
                p = data + len - 1;

                break;

            case s_message_done:
                UPDATE_STATE(NEW_MESSAGE());
                CALLBACK_NOTIFY(message_complete);
                if (parser->upgrade)
                {
                    /* Exit, the rest of the message is in a different protocol. */
                    RETURN((p - data) + 1);
                }
                break;

            case s_chunk_size_start:
            {
                assert(nread == 1);
                assert(parser->flags & F_CHUNKED);

                unhex_val = unhex[(unsigned char) ch];
                if (UNLIKELY(unhex_val == -1))
                {
                    SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
                    goto error;
                }

                parser->content_length = unhex_val;
                UPDATE_STATE(s_chunk_size);
                break;
            }

            case s_chunk_size:
            {
                uint64_t t;

                assert(parser->flags & F_CHUNKED);

                if (ch == CR)
                {
                    UPDATE_STATE(s_chunk_size_almost_done);
                    break;
                }

                unhex_val = unhex[(unsigned char) ch];

                if (unhex_val == -1)
                {
                    if (ch == ';' || ch == ' ')
                    {
                        UPDATE_STATE(s_chunk_parameters);
                        break;
                    }

                    SET_ERRNO(HPE_INVALID_CHUNK_SIZE);
                    goto error;
                }

                t = parser->content_length;
                t *= 16;
                t += unhex_val;

                /* Overflow? Test against a conservative limit for simplicity. */
                if (UNLIKELY((ULLONG_MAX - 16) / 16 < parser->content_length))
                {
                    SET_ERRNO(HPE_INVALID_CONTENT_LENGTH);
                    goto error;
                }

                parser->content_length = t;
                break;
            }

            case s_chunk_parameters:
            {
                assert(parser->flags & F_CHUNKED);
                /* just ignore this shit. TODO check for overflow */
                if (ch == CR)
                {
                    UPDATE_STATE(s_chunk_size_almost_done);
                    break;
                }
                break;
            }

            case s_chunk_size_almost_done:
            {
                assert(parser->flags & F_CHUNKED);
                STRICT_CHECK(ch != LF);

                parser->nread = 0;
                nread = 0;

                if (parser->content_length == 0)
                {
                    parser->flags |= F_TRAILING;
                    UPDATE_STATE(s_header_field_start);
                }
                else
                {
                    UPDATE_STATE(s_chunk_data);
                }
                CALLBACK_NOTIFY(chunk_header);
                break;
            }

            case s_chunk_data:
            {
                uint64_t to_read = MIN(parser->content_length,
                                       (uint64_t)((data + len) - p));

                assert(parser->flags & F_CHUNKED);
                assert(parser->content_length != 0 && parser->content_length != ULLONG_MAX);

                /* See the explanation in s_body_identity for why the content
         * length and data pointers are managed this way.
         */
                MARK(body);
                parser->content_length -= to_read;
                p += to_read - 1;

                if (parser->content_length == 0)
                {
                    UPDATE_STATE(s_chunk_data_almost_done);
                }

                break;
            }

            case s_chunk_data_almost_done:
                assert(parser->flags & F_CHUNKED);
                assert(parser->content_length == 0);
                STRICT_CHECK(ch != CR);
                UPDATE_STATE(s_chunk_data_done);
                CALLBACK_DATA(body);
                break;

            case s_chunk_data_done:
                assert(parser->flags & F_CHUNKED);
                STRICT_CHECK(ch != LF);
                parser->nread = 0;
                nread = 0;
                UPDATE_STATE(s_chunk_size_start);
                CALLBACK_NOTIFY(chunk_complete);
                break;

            default:
                assert(0 && "unhandled state");
                SET_ERRNO(HPE_INVALID_INTERNAL_STATE);
                goto error;
        }
    }

    /* Run callbacks for any marks that we have leftover after we ran out of
   * bytes. There should be at most one of these set, so it's OK to invoke
   * them in series (unset marks will not result in callbacks).
   *
   * We use the NOADVANCE() variety of callbacks here because 'p' has already
   * overflowed 'data' and this allows us to correct for the off-by-one that
   * we'd otherwise have (since CALLBACK_DATA() is meant to be run with a 'p'
   * value that's in-bounds).
   */

    assert(((header_field_mark ? 1 : 0) +
            (header_value_mark ? 1 : 0) +
            (url_mark ? 1 : 0) +
            (body_mark ? 1 : 0) +
            (status_mark ? 1 : 0)) <= 1);

    CALLBACK_DATA_NOADVANCE(header_field);
    CALLBACK_DATA_NOADVANCE(header_value);
    CALLBACK_DATA_NOADVANCE(url);
    CALLBACK_DATA_NOADVANCE(body);
    CALLBACK_DATA_NOADVANCE(status);

    RETURN(len);

error:
    if (HTTP_PARSER_ERRNO(parser) == HPE_OK)
    {
        SET_ERRNO(HPE_UNKNOWN);
    }

    RETURN(p - data);
}

/* Does the parser need to see an EOF to find the end of the message? */
static int http_message_needs_eof(const http_parser *parser)
{
    if (parser->type == HTTP_REQUEST)
    {
        return 0;
    }

    /* See RFC 2616 section 4.4 */
    if (parser->status_code / 100 == 1 || /* 1xx e.g. Continue */
        parser->status_code == 204 ||     /* No Content */
        parser->status_code == 304 ||     /* Not Modified */
        parser->flags & F_SKIPBODY)
    { /* response to a HEAD request */
        return 0;
    }

    if ((parser->flags & F_CHUNKED) || parser->content_length != ULLONG_MAX)
    {
        return 0;
    }

    return 1;
}

static int http_should_keep_alive(const http_parser *parser)
{
    if (parser->http_major > 0 && parser->http_minor > 0)
    {
        /* HTTP/1.1 */
        if (parser->flags & F_CONNECTION_CLOSE)
        {
            return 0;
        }
    }
    else
    {
        /* HTTP/1.0 or earlier */
        if (!(parser->flags & F_CONNECTION_KEEP_ALIVE))
        {
            return 0;
        }
    }

    return !http_message_needs_eof(parser);
}

static const char *
http_method_str(enum http_method m)
{
    return ELEM_AT(method_strings, m, "<unknown>");
}

static const char *
http_status_str(enum http_status s)
{
    switch (s)
    {
#define XX(num, name, string) \
    case HTTP_STATUS_##name:  \
        return #string;
        HTTP_STATUS_MAP(XX)
#undef XX
        default:
            return "<unknown>";
    }
}

static void
http_parser_init(http_parser *parser, enum http_parser_type t)
{
    void *data = parser->data; /* preserve application data */
    memset(parser, 0, sizeof(*parser));
    parser->data = data;
    parser->type = t;
    parser->state = (t == HTTP_REQUEST ? s_start_req : (t == HTTP_RESPONSE ? s_start_res : s_start_req_or_res));
    parser->http_errno = HPE_OK;
}

static void
http_parser_settings_init(http_parser_settings *settings)
{
    memset(settings, 0, sizeof(*settings));
}

static const char *
http_errno_name(enum http_errno err)
{
    assert(((size_t) err) < ARRAY_SIZE(http_strerror_tab));
    return http_strerror_tab[err].name;
}

static const char *
http_errno_description(enum http_errno err)
{
    assert(((size_t) err) < ARRAY_SIZE(http_strerror_tab));
    return http_strerror_tab[err].description;
}

static enum http_host_state
http_parse_host_char(enum http_host_state s, const char ch)
{
    switch (s)
    {
        case s_http_userinfo:
        case s_http_userinfo_start:
            if (ch == '@')
            {
                return s_http_host_start;
            }

            if (IS_USERINFO_CHAR(ch))
            {
                return s_http_userinfo;
            }
            break;

        case s_http_host_start:
            if (ch == '[')
            {
                return s_http_host_v6_start;
            }

            if (IS_HOST_CHAR(ch))
            {
                return s_http_host;
            }

            break;

        case s_http_host:
            if (IS_HOST_CHAR(ch))
            {
                return s_http_host;
            }

        /* fall through */
        case s_http_host_v6_end:
            if (ch == ':')
            {
                return s_http_host_port_start;
            }

            break;

        case s_http_host_v6:
            if (ch == ']')
            {
                return s_http_host_v6_end;
            }

        /* fall through */
        case s_http_host_v6_start:
            if (IS_HEX(ch) || ch == ':' || ch == '.')
            {
                return s_http_host_v6;
            }

            if (s == s_http_host_v6 && ch == '%')
            {
                return s_http_host_v6_zone_start;
            }
            break;

        case s_http_host_v6_zone:
            if (ch == ']')
            {
                return s_http_host_v6_end;
            }

        /* fall through */
        case s_http_host_v6_zone_start:
            /* RFC 6874 Zone ID consists of 1*( unreserved / pct-encoded) */
            if (IS_ALPHANUM(ch) || ch == '%' || ch == '.' || ch == '-' || ch == '_' ||
                ch == '~')
            {
                return s_http_host_v6_zone;
            }
            break;

        case s_http_host_port:
        case s_http_host_port_start:
            if (IS_NUM(ch))
            {
                return s_http_host_port;
            }

            break;

        default:
            break;
    }
    return s_http_host_dead;
}

static int
http_parse_host(const char *buf, struct http_parser_url *u, int found_at)
{
    enum http_host_state s;

    const char *p;
    size_t buflen = u->field_data[UF_HOST].off + u->field_data[UF_HOST].len;

    assert(u->field_set & (1 << UF_HOST));

    u->field_data[UF_HOST].len = 0;

    s = found_at ? s_http_userinfo_start : s_http_host_start;

    for (p = buf + u->field_data[UF_HOST].off; p < buf + buflen; p++)
    {
        enum http_host_state new_s = http_parse_host_char(s, *p);

        if (new_s == s_http_host_dead)
        {
            return 1;
        }

        switch (new_s)
        {
            case s_http_host:
                if (s != s_http_host)
                {
                    u->field_data[UF_HOST].off = (uint16_t)(p - buf);
                }
                u->field_data[UF_HOST].len++;
                break;

            case s_http_host_v6:
                if (s != s_http_host_v6)
                {
                    u->field_data[UF_HOST].off = (uint16_t)(p - buf);
                }
                u->field_data[UF_HOST].len++;
                break;

            case s_http_host_v6_zone_start:
            case s_http_host_v6_zone:
                u->field_data[UF_HOST].len++;
                break;

            case s_http_host_port:
                if (s != s_http_host_port)
                {
                    u->field_data[UF_PORT].off = (uint16_t)(p - buf);
                    u->field_data[UF_PORT].len = 0;
                    u->field_set |= (1 << UF_PORT);
                }
                u->field_data[UF_PORT].len++;
                break;

            case s_http_userinfo:
                if (s != s_http_userinfo)
                {
                    u->field_data[UF_USERINFO].off = (uint16_t)(p - buf);
                    u->field_data[UF_USERINFO].len = 0;
                    u->field_set |= (1 << UF_USERINFO);
                }
                u->field_data[UF_USERINFO].len++;
                break;

            default:
                break;
        }
        s = new_s;
    }

    /* Make sure we don't end somewhere unexpected */
    switch (s)
    {
        case s_http_host_start:
        case s_http_host_v6_start:
        case s_http_host_v6:
        case s_http_host_v6_zone_start:
        case s_http_host_v6_zone:
        case s_http_host_port_start:
        case s_http_userinfo:
        case s_http_userinfo_start:
            return 1;
        default:
            break;
    }

    return 0;
}

static void
http_parser_url_init(struct http_parser_url *u)
{
    memset(u, 0, sizeof(*u));
}

static int http_parser_parse_url(const char *buf, size_t buflen, int is_connect,
                                 struct http_parser_url *u)
{
    enum state s;
    const char *p;
    enum http_parser_url_fields uf, old_uf;
    int found_at = 0;

    if (buflen == 0)
    {
        return 1;
    }

    u->port = u->field_set = 0;
    s = is_connect ? s_req_server_start : s_req_spaces_before_url;
    old_uf = UF_MAX;

    for (p = buf; p < buf + buflen; p++)
    {
        s = parse_url_char(s, *p);

        /* Figure out the next field that we're operating on */
        switch (s)
        {
            case s_dead:
                return 1;

            /* Skip delimeters */
            case s_req_schema_slash:
            case s_req_schema_slash_slash:
            case s_req_server_start:
            case s_req_query_string_start:
            case s_req_fragment_start:
                continue;

            case s_req_schema:
                uf = UF_SCHEMA;
                break;

            case s_req_server_with_at:
                found_at = 1;

            /* fall through */
            case s_req_server:
                uf = UF_HOST;
                break;

            case s_req_path:
                uf = UF_PATH;
                break;

            case s_req_query_string:
                uf = UF_QUERY;
                break;

            case s_req_fragment:
                uf = UF_FRAGMENT;
                break;

            default:
                assert(!"Unexpected state");
                return 1;
        }

        /* Nothing's changed; soldier on */
        if (uf == old_uf)
        {
            u->field_data[uf].len++;
            continue;
        }

        u->field_data[uf].off = (uint16_t)(p - buf);
        u->field_data[uf].len = 1;

        u->field_set |= (1 << uf);
        old_uf = uf;
    }

    /* host must be present if there is a schema */
    /* parsing http:///toto will fail */
    if ((u->field_set & (1 << UF_SCHEMA)) &&
        (u->field_set & (1 << UF_HOST)) == 0)
    {
        return 1;
    }

    if (u->field_set & (1 << UF_HOST))
    {
        if (http_parse_host(buf, u, found_at) != 0)
        {
            return 1;
        }
    }

    /* CONNECT requests can only contain "hostname:port" */
    if (is_connect && u->field_set != ((1 << UF_HOST) | (1 << UF_PORT)))
    {
        return 1;
    }

    if (u->field_set & (1 << UF_PORT))
    {
        uint16_t off;
        uint16_t len;
        const char *p;
        const char *end;
        unsigned long v;

        off = u->field_data[UF_PORT].off;
        len = u->field_data[UF_PORT].len;
        end = buf + off + len;

        /* NOTE: The characters are already validated and are in the [0-9] range */
        assert(off + len <= buflen && "Port number overflow");
        v = 0;
        for (p = buf + off; p < end; p++)
        {
            v *= 10;
            v += *p - '0';

            /* Ports have a max value of 2^16 */
            if (v > 0xffff)
            {
                return 1;
            }
        }

        u->port = (uint16_t) v;
    }

    return 0;
}

static void
http_parser_pause(http_parser *parser, int paused)
{
    /* Users should only be pausing/unpausing a parser that is not in an error
   * state. In non-debug builds, there's not much that we can do about this
   * other than ignore it.
   */
    if (HTTP_PARSER_ERRNO(parser) == HPE_OK ||
        HTTP_PARSER_ERRNO(parser) == HPE_PAUSED)
    {
        uint32_t nread = parser->nread; /* used by the SET_ERRNO macro */
        SET_ERRNO((paused) ? HPE_PAUSED : HPE_OK);
    }
    else
    {
        assert(0 && "Attempting to pause parser in error state");
    }
}

static int http_body_is_final(const struct http_parser *parser)
{
    return parser->state == s_message_done;
}

static unsigned long
http_parser_version(void)
{
    return HTTP_PARSER_VERSION_MAJOR * 0x10000 |
           HTTP_PARSER_VERSION_MINOR * 0x00100 |
           HTTP_PARSER_VERSION_PATCH * 0x00001;
}

static void
http_parser_set_max_header_size(uint32_t size)
{
    max_header_size = size;
}

#ifdef __cplusplus
}
#endif
#endif
